Update: I was unfortunately not aware of Shamus Young's severe criticism of Fallout 3 available here to link in the original piece and I regret that. It dovetails rather nicely with what I've written and it's much better executed than my piece. I strongly recommend anyone...

TricksTable Top Up + Square
Can-Can Right + Square
Back Flip Down + Square
Look Down Left + Square
Rocket Man AirUp Left + Square
SUperman Up, Right + Square
Tailwhip Air Down, Right + Square
Candy Bar Down, Left + Square
X-Up Up + O
X-Down Up, Up + O
One Hander Right + O
Swich Hander Right Right + O
Bar Spine Down + O
Bar Spin to Bar Spine Back Down Down + O
One Footer Left + O
Seat Grab Right Up + O
Double Seat Grab Right Up Right Up + O
Peg Grab Left Up + O
Double Peg Grab Left Up Left Up + O
No Footer Left Down + O
No Hander Right Down + O
Tooth Pick Grind Up + Triangle
Feeble Grind Right + Triangle
Double Peg Grind Down + Triangle
Smith Grind Left + Triangle
Luc-e Grind Up Right + Triangle
Sprocket Grind Down Right + Triangle
Crooked Grind Down Left + Triangle
Lip Slide Up Left + Triangle
Spin Right R1/R2
Spin Left L1/L2
CombosTruck Driver Down + O + shoulder buttons
Flair Down + Square + 180 spine Left or Right
Nothing Down, Left + Down, Right

No Footed Seat Grab (looks better than super man seat grab):
Down Left + Up Right.

Double Seat Grab Super Man (hard to do, you have to push the buttons
fast):
Up Right + Square then Up, Right, Up, Right + O.

Jump Off Your Bike:
To jump off your bike, while you are in the air, press L2 + R2. "This
makes for some pretty gnarly crashes!"

Nose Wheelie:
Jump and while in the air press and hold the X and Up buttons.

Fastplant:
When coming down after catching some mad air on a half pipe, or a quater
pipe press and hold down Left and X. This also works with ledges.

Wall Tap:
This is basically the same thing as the Fastplant, but instead of Left +
X, you hold down Right + X.

Hints

Ride on the Wall:
When you begin, go straight. There should be 2 ledges, go on the high ledge
(they are covered with dirt). Keep going down the path holding no buttons
but Up and Triangle. Keep holding the Triangle and Up buttons when you reach
the little 1/4 pipe connecting to the wall. you should then be riding the
wall, and if you fall, you will get a "player cratered" message. Cool!

Slim and the Bonus:
Beat the game with anyone and you will unlock a guy called Slim Jim and
a bonus bike.

Unlock The Amish Boy:
Beat the game with all ten original riders.

Unlock Hidden Features:
Beat the game with riders other than D.Mirra, Slim Jim, or R. Nyquist to
open modes such as night vision or exorcist mode.